This invention relates generally to devices for handling and counting discrete articles, and more particularly to a novel and improved can end handling apparatus capable of receiving a continuous flow of can ends either in a nested or stacked condition or individually, and delivering a stack of nested and accurately counted can ends to a packaging or bagging station.
In the manufacture of cans, the bodies and ends of the cans are generally separately fabricated and packaged for later assembly in connection with the filling process. Generally speaking, the producer of the canned product purchases the necessary number of can bodies and can ends for subsequent assembly. The bodies may have one end preformed in the material of the body or one end pre-attached when a cylindrical, open-ended type of body is used. It is therefore necessary that the number of separate can ends delivered to the producer be substantially equal to the number of can bodies delivered, so that production runs are not interrupted due to an insufficient supply of ends.
As mentioned, the can ends are shipped pre-packaged, preferably in a stacked or nested condition in elongated kraft paper bags. Preferably, each bag should contain substantially the same, preselected number of ends. Often the can ends are shipped in lots or bags of 300 or more. It is preferable that, regardless of the size of the bag, a relatively accurate count of can ends be maintained within a relatively small margin over a relatively large number of bags forming a given shipment or order. Since the number of can ends in a given order or shipment may run into the millions, it will be appreciated that manual counting of the can ends in each bag is impractical.
While a number of mechanized or automated counting methods were employed and attempted in years past, none has proven particularly reliable or workable, until relatively recently. More recently, we developed a novel and reliable apparatus for counting and packaging can ends, as shown and described in our U.S. Pat. No. 3,971,189, issued July 27, 1976. While this apparatus has found widespread commercial acceptance, there is room for further improvement. In particular, the increasing use of cans having ends with preformed tab-like closures, often popularly called "pop-top" cans has given rise to some additional problems. These tab-like closures may be completely removable, or may be designed to be retained on the can end following opening thereof. In either instance, the provision of can ends with such tabs preformed thereon has created some novel problems in the handling, counting and packaging or bagging of can ends.
More specifically, it is generally desirable that the can ends be handled and packaged in a stacked or nested condition. In this regard, the peripheral edge of each can is generally formed in a reversely bent edge known as the "curl". It is desired that the ends nest in an abutting curl-to-curl relationship to form a relatively compact stack of ends. This relatively closely stacked or nested condition of the can ends generally permits preformed stacks or "sticks" as they are often called in the art, to be relatively easily fed through conveyor systems utilizing generally tubular or arcuate trough-like guides or the like.
However, it will be appreciated that the additional provision of a slightly protruding tab member on one surface of the can end tends to make the desired nesting or stacking more difficult to achieve and maintain. This occurs because the tabs often become spaced outwardly somewhat from the surface of the can and take a slight set such that a slight spring-like action is experienced when the cans are pressed together into the desired nested or stacked condition. Moreover, the outermost extent of the tab relative to the can end surface is usually off center somewhat, such that the spring-like action tends to cause relative tilting or canting of one can end relative to the next adjacent can end in a stack or stick. Accordingly, should the can ends in a stack become sufficiently separated during handling, or should one or more leading or trailing ends in a stick begin to tilt or cant due to the above-described action of the preformed tabs, clogging or jamming of the handling equipment may result. Such clogging or jamming requires a shutdown of relatively high speed production and handling equipment to correct the problem, and this is relatively expensive, time consuming and hence undesirable.
Advantageously, our present invention provides for the handling and counting of can ends while maintaining the same in the desired closely stacked or nested condition throughout the handling and counting procedure. Hence, the invention not only prevents relatively costly clogging and jamming of the machinery due to tilted or dislodged can ends, but also maintains a relatively accurate count of ends fed to a bagging or packaging station.